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Stainless steel – a mainstay in water assets

A mainstay in the processing of sewage water in water recycling applications, stainless steel once again plays a critical part in working towards a sustainable future.

Western Water Treatment Plant (WWTP), south of Werribee in Melbourne’s Western District, is a critical asset responsible for processing around half of the city’s total sewage. The process requires a massive footprint, where a series of large lagoons use anaerobic (without oxygen) and aerobic (with oxygen) bacteria to sequentially break down and clean the feed water of solids and gases. The resultant recycled water is used for multiple non-drinking purposes, including irrigation and firefighting. 

WWTP is also largely energy self-sufficient. This energy is captured during the sewage treatment process by combusting biogas, which is captured under the covers. Biogas is used to meet much of the Plant’s electricity needs – preventing hundreds of thousands of tonnes of carbon dioxide entering the atmosphere each year. 

The site carries significant environmental importance to both the immediate and wider areas. Biogas production from the process is used to meet all the Plant’s energy needs through on-site power generation. The Plant is an enormous site – almost the same size as Phillip Island and a world-renowned wetland, declared a Ramsar site in 1983. It is home to many species of flora and fauna and a haven for birdwatchers – in summer it can host more than 100,000 birds in a month.

With current capacity concerns in the existing plant network, stretching back 120 years, and a forecasted increase in processing demands due to a growing city, the need for an additional nutrient removal plant (to complement the existing two) was established. More efficient in design and with more advanced monitoring and controls to provide class A recycled water, the new plant provides an additional 140ML of treated water per day. The plant was designed by Jacobs and built by UGL and CBP Contractors, with commissioning in 2019.

Grade 316L stainless steel was selected as a default material for the pipework, in 2B finish. Offering strong corrosion resistance even against contaminated effluent water, its ease of fabrication and ability to be installed without the need for coating and subsequent maintenance was also important.

ASSDA Member and Accredited Fabricator Roladuct Spiral Tubing was selected to manufacture and supply approximately 50t of spiral welded large diameter pipe, ranging from 300 to 1422mm in diameter. Feed material was supplied  by ASSDA Member, Midway Metals to Roladuct’s  Melbourne manufacturing site. 

Roladuct was nominated in 2019 for the ASSDA Fabricator Project of the Year Award, with judges impressed by the quantity of stainless steel used, as well as the significant environmental benefits realised by the plant upgrade.

As water assets continue to be upgraded and optimised for a growing country, stainless steel will continue to play a vital role in providing material performance and plant reliability for years to come.

 

 Photo credit: Roladuct Spiral Tubing

This article is featured in Australian Stainless Magazine issue 71, 2021.

 

Screening Melbourne’s drinking water

Stainless steel is playing a vital role in delivering effective bulk water intake screens for Melbourne’s water supply.

Designed and manufactured in Brisbane, ASSDA Member Aqseptence Group Australia has recently delivered one of the largest passive intake screens in the Southern Hemisphere. Having produced more than 4,000 screens for the last  50 years, this latest milestone achieved a nomination in the hotly contested Process Industries category of the 2019 ASSDA Fabricator Project of the Year Award. 

In mid-August 2019, Aqseptence Group was engaged by a joint venture of John Holland and KBR to provide design and construct services for a significant capital works project, covering multiple Melbourne Water assets. The screen is used as a bulk water transfer screen for the O’Shannassy Dam, located east of Melbourne. Distributing clean drinking water  to most parts of Melbourne, it is a critical asset storing  3.1 gigalitres of water among a series of reservoirs on the city’s periphery. The mammoth screen took  approximately two months to design and manufacture.

The Johnson Screens T96E passive intake measures an impressive 8.6 metres wide and stands 3.6 metres high.  It is constructed entirely in grade 316L with a mill finished  plate and No. 4 finish wedge-wire and bar. K-Tig welding  was used to join 10mm plates to achieve overall plate size  to roll into tubes. The entire fabrication was then pickled  and passivated. Grade 316L, a standard material of construction at Aqseptence Group, was specified for the grade’s ability to resist general and localised forms of corrosion, a risk even with relatively low chloride inland  water sources. Additionally, being easy to source and  fabricate, its versatility in taking many forms and profiles  is clearly on display.

The intake screen is used to provide an uninterrupted water withdrawal source while protecting assets from foreign matter and most importantly, protecting wildlife by guaranteeing uniform and low through-flow velocities. This fish-friendly screen is also a passive design as it has no moving parts, therefore simplifying maintenance and reliability. Aqseptence Group’s Vee-Wire slot system was used to ensure uniform flow through the screen at a controlled velocity, to protect surrounding marine life. Additionally, using the strength properties of 316L, the screen has sufficient mechanical rigidity to support its own weight along with hydrostatic pressures. Stainless steel was specified due to its low impact on the environment, on both the reservoir and the clean drinking water it supplies, paired with its durability, corrosion  resistance and material strength attributes.

Aqseptence Group is now focused on working with the broader network of water infrastructure authorities to help upgrade their water supply assets and continue to service  the City of Melbourne for future generations with the use of stainless steel.

This article is featured in Australian Stainless Magazine issue 70, 2020.

 

Stainless steel - The right choice for an environmentally sustainable upgrade

Stainless steel provides a cutting edge and environmentally friendly solution for industrial applications.

Dow Chemicals, a global chemicals manufacturer, recently completed a major upgrade of the wastewater treatment system at their Victorian Point Henry coatings plant. The plant manufactures acrylic emulsions which find use in numerous applications including house paints. ASSDA Members Stirlings Performance Steels and Barwon Valley Stainless provided supply and fabrication services for this impressive wastewater treatment facility upgrade. 

Wastewater produced in the production facility is pumped into flocculation tanks for settling and the clear supernatant is sent for further biological treatment. This treated water is recycled back to production but is also used for irrigation on site to minimise freshwater consumption.

Geelong based Barwon Valley Stainless is a preferred Dow contractor and was selected to provide the complete scope of services for the wastewater treatment plant upgrade due to their knowledge and expertise of wastewater treatments, both local and interstate. Their quality workmanship was reflected in this project as they provided civil and structural works, tank and pipe spooling fabrication, site installation and pump station commissioning. With over 25 years’ experience and competence in stainless fabrication, they were able to work successfully within Dow’s project time and location constraints. 

Stirlings Performance Steels supplied the entire portfolio of materials to Barwon Valley Stainless. This included cut-to-length large bore pipe, structural rectangular hollow section and various pipe fittings as well as laser/plasma profiled plate which were all in grade 316/L.

Reducing environmental footprint in industrial applications is important and material selection is a critical step in both maximising the lifetime of plant and equipment, while minimising the need for maintenance and servicing. This upgrade successfully satisfied both these requirements with the use of stainless steel. Grade 316 is a popular material of construction where water is processed with relatively low chlorides at ambient temperature. It provides an optimal cost benefit compared with other steel-based alternatives which require coating or lining. Additionally, the close proximity of the site to Victoria’s Corio Bay requires resistance to corrosion from airborne seawater. According to Ben Arlidge, Project Manager at Dow, “Stainless steel has provided the perfect mix of performance, workability and cost for our new wastewater treatment facility.”

The plant upgrade is a major step in providing long term certainty to the local Moolap economy, as well as in strengthening the Australian supply chain of domestic market paint products. 

 

Photo credit: Barwon Valley Stainless

This article is featured in Australian Stainless Magazine issue 70, 2020.

A stainless approach to protecting the environment

Safeguarding Australia’s environmental biosecurity is critical in preventing the introduction and spread of pests and diseases, and the Post Entry Quarantine (PEQ) facility in northern Melbourne is setting the benchmark in international best practice with the use of stainless steel.

The PEQ facility in Mickelham is a state-of-the-art, purpose-built operation constructed to streamline the country’s quarantine services and consolidate five pre-existing Commonwealth PEQ facilities spread across New South Wales, Victoria, South Australia and Western Australia. Managed by the Department of Agriculture and Water Resources, the 144ha site includes an administration building, modern laboratories, dog and cat receiving areas, horse facilities and separate compounds for birds, ruminants, bees, plants, horse veterinarians and dogs and cats. Today, as Australia’s flagship quarantine control centre, the integrated PEQ facility is the first point of entry for all imported animals, plant material and insects entering the country, providing secure accommodation and biological containment.

One of the more challenging aspects of the PEQ facility’s construction was the design and build of the avian compound. The complex and demanding brief included the delivery of five high-criticality biocontainment units under Quarantine Containment Level 3 (QC3) requirements, the highest level of biosecurity containment. Containment of micro-organisms and prevention of their release is of utmost importance. Mitigating and eliminating risk of exotic pathogens and disease connected to avian imports such as fertile eggs and live birds is critical.

In association with UK-based Suncombe Engineering, a worldwide leader in the field of wastewater decontamination, ASSDA Member Fineweld Stainless Steel was engaged by hydraulics contractor Geschke Plumbing to supply, manufacture, and install the wastewater decontamination plant system and connecting containment pipework for the treatment of QC3 biowaste products in the avian compound.

The wastewater decontamination plant system required a 12,500L collection vessel and 1,750 heat treatment vessel, and the collection vessel was fabricated from 316 grade and the treatment vessel from 2205 duplex stainless steel with a 2B 0.6μm finish in Fineweld Stainless Steel’s Carrum Downs workshop. Following manufacture, the treatment vessel was packaged and transported to Suncombe Engineering in the UK for final assembly into the wastewater decontamination plant and to undergo a complete Factory Acceptance Test (FAT) as a certified testing authority. The wastewater decontamination plant was then transported back to Fineweld Stainless Steel in Australia for pre-testing at their facility and then installation on site.

In addition to the two vessels, Fineweld Stainless Steel installed and welded the connecting pipework on site, manufactured from 5t of 316 grade stainless steel. All pipework welded joints – approximately 1,500 butt welds – were orbital welded and each one inspected, tested and recorded as part of the project scope to comply with the client’s strict QC3 requirements. QC3 facilities use gaseous decontaminants including vaporised hydrogen peroxide and chlorine dioxide. The use of stainless steel offers material strength, hygiene and resistance to both corrosion and the chemicals required to deactivate pathogens, whilst ensuring a gas-tight system for fumigable ductwork.

The installation took place two stories underground, therefore manufacturing and pre-spooling had no margin of error. Extensive logistical challenges were diligently managed, and in collaboration with Suncombe Engineering and Geschke Plumbing, the project was delivered on-time and on budget by the Fineweld Stainless Steel team.

In what would have been traditionally manufactured and imported from overseas suppliers, Fineweld Stainless Steel is showcasing the high quality and technical capability of Australian stainless steel manufacturing, producing high-end pressure vessels and complex works for a demanding and precise application. World-class infrastructure demands high quality products and long-term asset performance, both of which have been successfully delivered for the avian compound of Mickelham’s PEQ Facility through superior local workmanship and the use of stainless steel.

 

 

Photo credit: Geschke Plumbing

This article is featured in Australian Stainless Magazine issue 69, 2020.

 

Running Water

Water authorities tackle water shortages with stainless steel.

Water is a fundamental human need. It is central to our lives, from what we drink, to what we use in washing ourselves, our clothes and a multitude of other uses. Safe, clean and palatable water comes at a price though, and when leaks occur in distribution systems, additional costs are incurred as even more water must be found and treated. Security of water supply is a prerequisite for sustainable growth and dealing with leakage is a universal challenge. To combat the scourge of leaks, a number of water distribution authorities across the world have implemented affordable solutions utilising stainless steel, which not only saves money, but water, a precious resource.

Tokyo, Japan

Prior to the 1980’s, water shortages in Tokyo were chronic and rationing was occasionally required. When the city’s water provider, the Tokyo Metropolitan Government Waterworks Bureau (TMGWB), analysed leakage repairs, they determined that 97% were on the distribution pipes of 50mm diameter or less. In Tokyo, there are more than two million such connections that take the water from the mains to internal systems in buildings. Historically, lead pipe was the preferred material for distribution lines because it is soft, malleable and easy to work with, especially for the last few metres from the mains to buildings. Once lead pipe is in the ground, however, various forces can act on it. Vibrations from traffic and construction work as well as subsidence and earthquakes can cause the soft lead pipes to deform, become detached or even break.

In 1980, TMGWB started to actively replace all service connections with grade 316 (UNS S31600) stainless steel pipe. In 1998 corrugated grade 316 (S31600) stainless steel pipe was introduced for distribution lines that take water from the mains to final destinations in homes, offices and industrial plants. The pipe is corrugated at regular intervals to allow for it to be bent during installation, to accommodate changes in direction and the avoidance of obstacles without additional joints. It also allows for movement of the pipe during earth movement and seismic events. By supplying a single length of corrugated stainless steel pipe, the number of pipe joints was greatly reduced. In switching to stainless steel pipe, the reliability of the water supply has increased and the leakage rate has been reduced by 86% from 15.4% (1980) to 2.2% (2013). To put this into context, since 1994 Tokyo has reduced annual water leakage by nearly 142 million cubic metres - the equivalent of 155 Olympic-size swimming pools per day, with savings in excess of US$200 million per year. Also, annual leak repairs have decreased from 60,000 (1983) to 10,000 (2013). Due to the corrosion resistance of stainless steel, TMGWB expects service life in excess of 100 years.

Graph below: Correlation between repair cases, leakage rates and installation of stainless steel pipes in Tokyo.
Courtesy of the Bureau of Water Works, Tokyo Metropolitan Government.

 

Taipei, Taiwan

In 2002, a severe drought brought intermittent water supplies to the Taiwanese capital over a 49-day period. Of the 450 metering areas in the city, 40% were losing half of their water or more before it reached consumers.

Analysis of repair cases showed that while polybutylene pipe made up only 3% of the length of the system, it accounted for 28% of all leaks. Approximately 90% of all problems occurred in plastic pipes, with the vast majority (83%) caused by cracking.

In 2003, the Taipei Water Department began a similar program to Tokyo, replacing distribution lines with corrugated grade 316L (S31603) stainless steel pipe. Although the ongoing program has so far only replaced 35% of the lines, the result has been a reduction in water loss from 27% (2003) to 17% (2014). This adds up to an annual saving of 146 million cubic metres of water, the equivalent of 160 Olympic-size swimming pools per day.

In 2014, a drought occurred with even less rainfall than the 2002 event which precipitated the pipe replacement program. However this time, the improvement in leakage rates achieved since 2003 meant there was no interruption to the water supply.

The 2002 drought in Taipei caused severe water shortages.
Image courtesy of the Taipei Water Department.

 

Western Cape, South Africa

South Africa is by nature a semi-arid country; its annual rainfall is only half the global average. It has a population of 55 million and is facing freshwater scarcity. It is estimated that at least 37% of its clean drinkable water is lost due to leakage from old and unreliable infrastructure.

The Groot Drakenstein Valley is the cradle of the South African deciduous fruit and wine industries. Water is supplied to over 800 farms including 50 vineyards. Here, there are numerous examples of carbon steel and cast iron pipes that have failed in many areas after just one year due to the very aggressive acidic soils and high water table. “We started a project in 1992 in the Drakenstein Municipality to replace existing piping with stainless steel,” explains André Kowalewski, Senior Engineer - Water Services, Drakenstein Municipality. “We have reduced water loss to around 13% in comparison to the 37% national average. Ten years back only the Drakenstein Municipality used stainless steel. Now 80% of the Western Cape municipalities do.”

André and his team plan for a life expectancy in excess of 50 years. Stainless steel used in Drakenstein is primarily grade 316 and in some cases grade 304 (S30400) in visible locations. Projects are currently focussed around pumping, purification, storage, pipelines and sewage. One such project is a 500 mega-litre/day delivery system completely in grade 316 stainless steel.

Stainless steel pipe in the Western Cape resists aggressive acidic soil conditions.
Images courtesy of Johan Van Zyl.

   

 

Investing in the future

The experience of Tokyo, Taipei and the Western Cape gives water authorities the confidence to specify stainless steel for piping systems. While the initial cost compared to competing materials may be higher, stainless steel has been shown to be a good investment over its long life, paying back each year in reduced maintenance and cost per litre processed.

This article was originally printed in Nickel Magazine (August 2016, Vol. 31, No.2), published by ASSDA Sponsor Nickel Institute.

This article is featured in Australian Stainless Issue 57 (Spring 2016).

Banner image: Corrugated pipe installation. Image courtesy of Tokyo Suido Services/Showarasekan.

Stainless Steel in Western Australia Subsea Applications

Stainless steel is the material of choice for subsea hydraulic and control line applications because of its excellent corrosion resistance, material strength benefits and weldability.

 Subsea production in the oil and gas industry involves offshore, in situ equipment to facilitate the exploration, development, production and transportation of energy reserves from underwater fields. It is a viable form of oil and gas production, providing economic, productivity and environmental benefits.

Perth-based ASSDA Member and Accredited Fabricator Diverse Welding Services (DWS) recently completed detailed design and fabrication works on two major subsea projects operated by multinational oil and gas exploration and production companies.

Apache Corporation’s Coniston and Novara Redevelopment Project, completed in February 2014, is a subsea oil field located 65km north of Exmouth. The project involved an upgrade to the Ningaloo Vision floating production, storage and offloading (FPSO) unit and development of the neighbouring Coniston and Novara oil fields, which links these fields into the existing Van Gogh manifolds via dual production flow lines. The equipment operates in water 340 to 400m deep.

DWS was contracted to detail the design, fabrication, installation and NDT testing of the small-bore hydraulic control and chemical injection lines for five subsea production manifolds.

2,380m of 316L stainless steel wall tube in various sizes ranging from 0.375” OD x 0.083” up to 1.000” OD x 0.156” was used, plus 30m of Inconel 625 0.750” OD x 0.134” wall tube.

Chevron Australia’s Wheatstone Project, located 12km west of Onslow on the Pilbara coast of Western Australia, is one of Australia’s most significant LNG projects. Currently in progress and at almost 60% complete, it will become the country’s first third party natural gas hub. DWS was contracted to fabricate, install and test small-bore tubing and free issue components to Multiple Quick Connect (MQC) plates. The main free issue components consisted of logic caps, cobra heads, single line couplers and acid injection items requiring small-bore interconnecting tubing on four MQC plates serving the subsea isolation valves (SSIV) for the 44” trunkline, 24” and 14” flowlines, and the 18” APACHE/KUFPEC line.

SAF2507 super duplex stainless steel was used for the MQC plates including over 80m of 0.625” OD x 0.083” wall tube, 20m of 316L 0.375” OD x 0.083” wall tube and 130 Swagelok 90° elbow butt-weld fittings. The MQC plates were fabricated by PT Profab Indonesia, then shipped to DWS in Perth for detailed fit-out using autogenous orbital welding processes. After testing, the completed MQC plates were shipped back to PT Profab Indonesia for installation into the SSIV manifolds.

All welding by DWS for both projects was completed using an autogenous orbital welding process, specified by the clients for the small-bore hydraulic tubing welding due to its excellent control of welding variables, repeatability of application and maximisation of corrosion resistance of exotic materials. DWS produced high quality welds that when tested under the G48 Method A – Pitting Resistance Testing, proved resulting weight loss to be less than 0.36g/m2.

Orbital welding is an automatic method of Tungsten Inert Gas (TIG) welding of thin tubes, usually without filler wire. Its advantages are a uniform weld profile and excellent gas shielding giving minimal heat tint. The ends of the tube are prepared and clamped in an enclosed head, which is flushed with external shielding and internal purging gas – usually argon, although gas mixtures can be used. The cycle starts by striking the arc and proceeds as the head slowly rotates around the tube. A specific weld head can deal with several diameter tubes. The weld is usually in the centre of the head, although heads are available for offset joins used with joints to elbows or valves.

DWS completed 1200 welds for the Coniston and Novara Redevelopment Project and 204 welds for the Wheatstone Project, which passed 100% radiographic/liquid penetrant testing in accordance with ASME B31.3 NFS. The excellent gas and heat input control of the orbital welding produced internal surfaces that did not require post-weld cleaning. The external surfaces around the welds were abrasively treated as required for aesthetics reasons.

The DWS facility includes five autogenous welding machines complimented with seven welding heads of assorted ranges allowing DWS to complete weldments from 0.25” OD to 6” OD tube/pipe schedules as required for these project works. This coupled with their extensive range of other qualified weld procedures for this process allows DWS to meet clients’ stringent fabrication, application and quality specifications.

         

This article is featured in Australian Stainless Issue 55 (Winter 2015).

Cutting a Carbon Footprint

Coca-Cola Amatil is reducing the carbon footprint of its 600ml PET bottles by 22% with the help of stainless steel.

Innovation in process technology and the successful application of stainless steel has led to efficiency gains and sustainable outcomes for one of the world's most recognised brands in the food and beverage industry.

In 2011, Coca-Cola Amatil (CCA) announced a $450 million investment in PET bottle self-manufacture, or ‘blowfill’ technology at its production facilities across Australia, New Zealand, Indonesia, Papua New Guinea and Fiji.

Blow-fill technology is a manufacturing technique that allows companies to produce their own PET (polyethylene terephthalate) bottles within their own facility. It allows manufacturers to form, fill and seal bottles in one continuous process at the one location without human intervention. Blow-fill has enabled CCA to make its PET bottles using significantly less PET resin, resulting in production of the lightest-weight bottles in the global Coca-Cola system.

Previously, CCA would buy blow-moulded bottles from a third party supplier, transporting them to its own facility to sterilise and fill with product. CCA’s integration of these three steps into one operation has automated its production lines, creating economies of scale and
optimising efficiencies of operation.

CCA’s Kewdale facility in Perth is one packaging line that recently completed its installation of blow-fill equipment, procured from Krones AG, a German-based process manufacturer.

CCA engaged ASSDA member and Accredited Fabricator TFG Pty Ltd for the installation and fabrication of the stainless steel interconnecting pipework for the facility’s new blow-fill equipment.

Sydney-based ME Engineering detailed the scope of works, and coordinated the process engineering and installation of the new equipment.

Over 6km of 304L and 316L AS1528 standard grade stainless steel tube was supplied by ASSDA sponsor Prochem Pipeline Products, ranging in size from 25mm-200mm diameter.

The TFG team purge TIG welded all stainless steel components on site and internally passivated the stainless steel using citric acid.

ME Engineering’s Project Manager Andrew Meagher said grade 316L was specified for CCA’s Kewdale facility because of the high chloride content of the water supply in Perth.

With spring water one of CCA’s main products, sanitation is key to avoiding microbiologically-influenced corrosion.

Tom Moultrie, General Manager of TFG, said that whilst there are other materials that can be specified for equipment using compressed air, stainless steel provides aesthetic appeal, trusted hygiene and longer life span.

The use of stainess steel has been successful in the output of this project, with CCA’s State Projects Engineer Simon Wall stating that ‘as a beverage manufacturer, food safety aspects of our processes and equipment are critical to ensuring the integrity and quality of our products – an area that stainless steel ensures.’

Kewdale’s new blow-fill line commenced operation in June 2012. It features 14 blowing stations, 108 filling nozzles and 18 capping stations, and has the capacity to produce 26,000 bottles per hour.

Mr Wall said the investment in PET bottle self-manufacture will continue to deliver savings in raw materials - bottles are made using less PET resin and less water is used in the bottling process - and meet future consumer growth and demand.

CCA’s ongoing commitment to innovation and sustainability has maximised production capabilities whilst minimising the use of resources.

By the end of 2012, 10 blow-fill lines will have been deployed across CCA’s production facilities in Australia, bringing self-sufficiency to over 70%. Once all 26 production lines are implemented, CCA estimates a saving of 7000 tonnes of PET resin per year, a 15% reduction in bottle weight and 50,000 truck movements eliminated per year. Overall, this is reducing the carbon footprint of every 600ml bottle by an average of 22%.

Images courtesy of TFG Pty Ltd.

This article is featured in Australian Stainless magazine, issue 52.

Helical Coil Gets a U-Neek Bend

Fabricating equipment for the chemical sector requires solid high quality materials and superior workmanship. In April 2011, ASSDA member and Accredited Fabricator U-Neek Bending Co Pty Ltd put the finishing touches on a radiant helical coil at their factory in Dandenong, Victoria.

The coil, designed as a heater for Titanium Tetrachloride (TiCl4) production, is 11.4 metres long with a diameter of 3.05 metres and required more than 7 tonnes of high grade Inconel Alloy.

U-Neek’s Business Development Manager, John Lovell, said the client chose to have this material shipped from America.
“At around US$1000 a metre, Inconel Alloy is a very expensive option but it has great heat transfer properties and is completely non-corrosive,” Mr Lovell said.

The Western Australian client, who declined to be named, were looking for a fabricator that, in addition to having a proven record in metal bending, could work to their particular requirements for this critical process componet.

“U-Neek weren’t just competitive in pricing,” said Greg, a project engineer with the client. “They succeeded with all the trial projects we sent them.”

“To ensure total quality control, we provided a comprehensive report that detailed every step of the process, including the names of every person who worked on the individual stages,” Mr Lovell said.

U-Neek Engineer Dale Theobold said the coil was manufactured to exacting tolerances using a range of Inconel Alloy materials.
“We used 150NB Schedule 40 seamless 600 for the pipes and flanges, 366-04 WPNCI-S for the elbows, B168-08 for the plate and 253MA for the high temperature pieces,” he said.

Once completed, the coil then had to undergo a rigorous series of tests. The butt welds were verified with full radiography, the attachment welds were submitted to liquid penetrant inspection (LPI), and a full hydro exam was done on the coil itself.

“The coil was filled with distilled water to test its heating capabilities. Then the coil was pressurised with nitrogen, to a dew point of -12°, to remove all traces of water and moisture prior to transporting,” Mr Lovell said.

The transport frame and mounting jigs were manufactured from mild steel. To ensure no cross contamination, Inconel strips were fitted to the mounting points. The coil was lifted onto the back of a semi-trailer for final transportation to Perth, using U-Neek’s 16 tonne travelling overhead cranes.

Images courtesy of U-Neek Bending Co Pty Ltd.

This article features in Australian Stainless magazine - Issue 50, Summer 2011/12.

Brewery to Excel with Local Fabrication

A worrying trend among Australia's major resource companies is the increasing amount of engineering, detailing and fabrication work being sent offshore - a move that has had significant impact on local fabrication. But there are some positive signs in the food and beverage sector that local fabricators are more than capable of meeting design and fabrication expectations.

When ASSDA member and Accredited Fabricator, A&G Engineering, put in a bid to build 10 x 100 hectolitre beer fermenters for Casella Estate - a company best known for their Yellowtail wine label - they had to compete against companies as far away as Europe for the coveted project.

But A&G had a few advantages over the offshore companies: they had worked with Casella before, fabricating 88 x 1.1 million litre wine tanks for the company’s tank farm in Yenda, NSW; they have supplied stainless steel tanks to Australia’s leading breweries, wineries and beverage companies; and they are one of the largest users of stainless steel in Australia.

A&G’s win is an important victory for the Australian industry as a whole and another milestone for A&G Engineering, which was founded in 1963.

The five-month Casella Brewery project, completed in August 2011, saw 25 of A&G’s 200 staff use 65 tonnes of 304 grade stainless steel (including 2-4mm coil and 8mm plate) to build the 10 vessels.

A&G’s Design Manager Heath Woodland said the tanks were designed to AS1210-2010 pressure vessel standards, in order to withstand a pressure rating of 115kPa.

The stainless was welded with A&G’s semi-automated welding process and the internal welds were polished to achieve a 0.6Ra surface finish, to meet beverage industry standards of a food grade finish.

A&G built the vessels at their Griffith and Irymple plants, before transporting them to Yenda. With the beer fermenters now in place, it is hoped the Casella Brewery will be operational by the end of 2011.

Images courtesy of A&G Engineering.

This article is featured in Australian Stainless magazine - Issue 50, Summer 2011/12.

Stainless a requirement for magnesium processing

A pilot magnesium processing plant is currently under production in Gladstone, using unique technology developed in Australia and incorporating a significant stainless steel component.

MagnesiumThe Australian Magnesium (AM) process (now owned by the Australian Magnesium Corporation - Brisbane, Qld) was jointly developed by Queensland Metals Corporation (QMC - Brisbane, Qld) and CSIRO to process the type of magnesite ore discovered by QMC near Rockhampton into highly pure magnesium metal.

The process incorporates a number of patented features which will be demonstrated and refined at the pilot plant in Gladstone on its completion in mid-1998. The AM process involves the use of a variety of harsh acids, requiring the specification of stainless steel grades such as 2205, 2507, 2RK65, 904L, 316L and 316H to withstand a range of corrosion environments.

Approximately $1.5 million has been spent on stainless steel components for the magnesium pilot plant, including stainless piping, pumps, compressors, tanks and shell and tube heat exchangers.

Eight fabricators supplied the components, including D & R Stainless (Salisbury, Qld), who fabricated seven stainless steel vessels using material ranging from 3mm to 13mm in thickness.

If the project progresses to full production of 90,000 tonnes of  magnesium per year, the plant will be 60 times larger than the pilot plant and the cost will expand to around $800 million. Construction is currently planned to commence towards the end of 1999 and commercial operations should begin at the end of 2002.

Magnesium is commonly used for automotive parts, such as instrument support panels, seat frames, transmission casings and rocker covers. Other common uses for magnesium are in laptop computer frames, chainsaw bodies and sporting equipment such as tennis racquets.

This article featured in Australian Stainless Issue 11, March 1998.

Duplex 2205 used for United Nations Navy Recompression Chambers

When the United States Navy required 35 lightweight transportable recompression chambers in the late 1980s, Cowan Manufacturing took up the challenge of developing the units. 

Cowan Manufacturing developed a prototype out of a virtually unknown material. It was duplex 2205 (UNS 31803) stainless steel.

No other manufacturer in the world was producing chambers out of 2205 and, after six years of negotiations, Cowan was sourced as the sole supplier of the chambers.

Cowan chose 2205 for its high strength, light weight and corrosion resistant properties. This enabled them to meet the Navy's requirements without the weight and corrosion problems of other materials.

Traditionally, recompression chambers have been made out of carbon steel and required high maintenance because of the severe marine environment in which they are used (on ships at sea). Chamber walls had to be thick to combat the effects of corrosion and so were very heavy.

The strength and corrosion resistance of 2205 over other materials enabled the chamber shell thickness to be reduced to 3mm. The thinner chamber walls effectively halved the weight of the units and corrosion resistance lengthened their service life.

However, Cowan faced some difficulties with the material because it was new on the market at the time. Staff had to be specially trained in welding techniques for the 2205 which had to be approved by Navy certification teams. (2205 is now a common material that is used for many industrial applications.)

The 2205 material was supplied by Sandvik Australia. The 3mm x 2000mm wide coil material was sized on its cut to length line and plasma arc cut the conical sections and the end cap discs which were then formed by Dome Engineering.

The strict quality requirements specified by the US Navy resulted in all material being ultrasonically examined and charpy tested before processing.

The chambers were produced at the Cowan Manufacturing facility at Warners Bay in New South Wales. Cowan has since become a specialist
in its field, supplying recompression chambers to 12 countries including the United States and Australia.

This article featured in Australian Stainless magazine - Issue 13, May 1999.

Stainless Supports Booming Wine Industry

15 million dollars worth of stainless steel has been used to construct the largest rotary fermentation area in Australia.

The facility at Southcorp's Karadoc Winery in Victoria comprises 88 stainless steel red grade processing tanks, pipes and tubes, brine jackets and rotary fermenters.

Southcorp Wines Engineering Manager (Eastern Region) Geoff Leighton said stainless steel was preferred by the wine industry because it is "corrosion resistant, provides a stable environment for the wine, is easy to clean and maintain and has a long service life."

Grade 304 stainless steel was used for the tanks, with a thickness range of 2mm - 6mm, with the highest tank 1 5 metres tall. An extensive amount of 304 and 316 tube was also used.

ASSDA members Atlas Steel (SA), Alfa Laval, APV Valves and James Contract Supplies were all involved in the project.

The expansion brings the Karadoc site's total storage capacity to approximately 93 million litres.

The winery, which produces known brands Lindemans, Queen Adelaide, Kaiser Stuhl and Matthew Lang exports approximately 60% of its bottled wine production.

"The project has provided infrastructure to the district and significant employment opportunities in the areas of viticulture, transport and production facilities," Mr Leighton said.

Mr Leighton said while stainless steel met the needs of the wine industry, there was room for improvement.

"Stainless steel demand exceeds supply on occasions," he said. "It is not totally corrosion resistant and requires diligence in the specification and fabrication process."

The Karadoc project is one example of current growth in the Australian wine industry, which has brought with it exciting opportunities for the stainless steel industry.

Domestic wine production has increased five fold since 1966, from 156 million litres to over 800 million litres.

Vision 2025, a strategic plan by the Australian wine industry, aims to make the industry a global force by achieving $4.5 billion in annual sales of wine and 6.5% of the value of world production by 2025.

Results to date have been positive, with 1999 total sales estimated to be approximately $2.4 billion and 3.5% of the world export volume.

The number and size of fabrication firms in wine growing regions is expanding and as such, real opportunities to explore new applications and methods of design, fabrication and maintenance exist.

To assist the wine and stainless industries meet their objectives, ASSDA is conducting "Using Stainless Steels in the Food Industry" seminar in May and June which will cover fabrication, corrosion, welding, cleaning and sanitation issues for stainless steel use in the food industries as well as issues specific to the wine industry.

For more information on ASSDA's "Using Stainless Steels in the Food Industry" Seminars, please contact ASSDA on (07) 3220 0722.

REFERENCES
1. Australian Wine Foundation (1996) Strategy 2025 - The Australian Wine Industry.

This article featured in Australian Stainless magazine - Issue 15, February 2000.

75 Tonne Stainless Tank Floor Built to Last

75 tonnes of stainless steel has been used to replace the floor in an enormous tank at QNI Limited's Yabulu Refinery near Townsville in North Queensland.

The tank is one of a series of seven thickener tanks, each of which is 50 metres in diameter. The purpose of the tanks is to form a counter current decant wash circuit for leached ore. Solid tailings are separated from liquor streams in the tanks which act as large settling devices, separating leached ore from a leached solution for the recovery of nickel and cobalt.

When the floor plate of one of the tanks was due to be replaced in June this year, QNI chose stainless steel for the job.

According to QNI's Deputy General Manager lan Skepper, the deciding factors in the choice of stainless were that it was relatively inexpensive and offered increased service life.

"The tanks have been in service for 25 years and the floor plates require replacement on a rolling basis," Mr Skepper said.

"They operate in a harsh environment, holding a solution which consists of strong ammonium hydroxide with up to 15 grams of sulphate per litre heated to 50 degrees celsius. This harsh chemical composition means that the floor plates suffer from severe corrosion and need to be replaced every 10 to 12 years.

"Traditionally we have used mild steel, but chose to use stainless this time because the material cost was not substantially higher particularly when the life expectancy of the floor will double due to the corrosion resistant properties of stainless."

Stainless steel was chosen also for its mechanical robustness and because it can be repaired or modified by workers who possess relatively standard trade skills.

To replace the floor plate, the tank had to be taken offline for six weeks resulting in reduced washing efficiencies and reduced metal recoveries at the refinery during this period.

"Future disruptions to the refinery due to replacements of thickener tank floor plates will now be reduced, because we expect the floor of this tank to last for at least 25 years," Mr Skepper said.

The job involved insitu welding of 5mm sheets of grade 304 stainless laid onto a sand bed.

The stainless steel for the project was supplied by Atlas Steels (Australia) Pty Ltd, Australian Stainless Steel Development Association Levy-paying members.

This article featured in Australian Stainless magazine - Issue 15, February 2000.

New Pulp Mill Relies on Stainless

1,200 tonnes of stainless steel plate and coil and over 47,000 metres of stainless steel pipe and tube has been used in the construction of a new $400 million unbleached pulp and paper mill in Tumut, New South Wales. 

The Visy Pulp and Paper Mill will produce 240,000 tonnes of unbleached kraft pulp and packaging paper annually, to be supplied to domestic and overseas markets.

Raw materials for the plant will come from local plantation timber sawmill residues and pulp materials from softwood plantations, and supplemented by domestic and commercially derived waste paper. The plant is being built using the latest technology, meeting the highest environmental standards.

Grades 304, 316 and 2507 stainless steel were used in pipes, storage tanks and vessels in the process area of the mill.

Approximately 1,200 tonnes of stainless steel plate and coil, ranging in thickness from three millimetres to 38 millimetres were used for the storage tanks. The storage tanks, 50 in total, have a capacity of nearly 30 000 cubic metres.

Grade 2507 stainless steel was used in smaller vessels that will contain highly concentrated liquids, sodium and potassium salts at high temperatures.

Visy Project Technical Manager Austin Davey said: "The combination of temperature and salt meant that 2507 was the only suitable material for the job."

304 stainless steel pipes will carry raw water, some chemicals and pulp used in the process.

Mr Davey said as well as its ability to deal with high temperatures and the corrosive environment of the plant, stainless steel was chosen for its cost-effectiveness and long life.

"We designed the mill to have at least a 30 year life, that's why we chose stainless," he said.

"We always look for the most cost-effective method for our projects.

"At the time of purchase, the price of stainless steel was very competitive and helped make the decision easy."

Fabrication was undertaken by a number of different companies in New South Wales, Queensland and Victoria.

Some of the piping for the mill was supplied by ASSDA member Skinner Engineering, with some storage tanks and vessels supplied by ASSDA members D&R Stainless and JC Butka Engineering Pty Ltd.

The majority of stainless steel used in the project was supplied by ASSDA member Sandvik Australia, with a proportion of the design work undertaken by ASSDA member Kvaerner.

Mr Davey said end users of stainless steel experience supply problems that he believes impact on the popularity of the material.

"Not all the materials or product forms are stocked in Australia. Lead times, availability and price movements must be watched."

The mill is expected to begin paper production in the middle of 2001.

This article featured in Australian Stainless magazine - Issue 17, January 2001.

 

 

The Workhorse of Hydrometallurgy


Posted 17 May 200

Stainless steel has earned a reputation as the material of choice for the mining and hydrometallurgical industries. This article discusses suitable grades and applications and the emerging opportunities for stainless steel in these industries.

Hydrometallurgy involves the extraction and refining of metals in aqueous solutions. It encompasses a range of processes such as leaching, solvent extraction, ion exchange, electrorefining, electrowinning, precipitation and solid/liquid separation for numerous metals including copper, zinc, nickel, cobalt, uranium, gold, silver, aluminium and rare earths. As stainless steel is the 'workhorse' material for many of these processes, especially those involving sulphuric acid solutions, hydrometallurgy is a significant market whose importance is growing as new processes are developed and applied.

HYDROMETALLURGY EXPANDING
Historically, metals extraction has been dominated by pyrometallurgical processes such as roasting and smelting, while hydrometallurgy has generally played a relatively minor role. However, since the 1950s, its role has expanded significantly, helped along by a string of new technical developments. These trends seem likely to continue as pyrometallurgical processes fall out of favour due to factors such as falling head grades, environmental pressure against gaseous emissions, the need to treat lower grades and impure ores, and the growing desire to add value by producing metals at the mine site. Significant growth areas for hydrometallurgy have been uranium ore processing in the 1950s, 1960s and 1970s, copper in the 1970s, 1980s and 1990s, and more recently nickel and cobalt.

TYPICAL APPLICATIONS
Uranium ores are almost exclusively treated by hydrometallurgy. The most common process is sulphuric acid leaching of finely ground material
at atmospheric pressure and temperatures up to about 800°C, followed by solid/liquid separation and solvent extraction or ion exchange. Stainless steels and high nickel alloys have been extensively used for tankage, pumps and piping.

Copper has traditionally been extracted from oxide ores by sulphuric acid leaching, either in agitated tanks or by spraying on heaps and dumps. Interest grew dramatically after the introduction of solvent extraction technology in the late sixties which, when coupled with electrowinning, enabled high grade copper cathode to be produced on site. More recently, this approach has been expanded to treat secondary sulphide ores such as chalcocite, and processes are now being developed for the treatment of chalcopyrite, the dominant copper mineral which is normally smelted. These new processes include pressure-oxidation, bio-oxidation and other novel leaching technology. Along with all of this has been the successful introduction of the use of stainless steel blanks for electrowinning and refining. Stainless steel is particularly suitable for copper in sulphuric acid solutions because of the inhibiting effect of copper in solution on corrosion.

Nickel and cobalt hydrometallurgy has been significantly boosted by a number of recent developments including the installation of new pressure acid leaching (PAL) operations for laterites in Western Australia, the first application of tank bio-leaching for cobalt recovery, the development of pressure-oxidation and bio-heap leaching technology for nickel sulphides. Although the PAL operations have had difficult start-ups, the PAL process is likely to become a major force in the future treatment of laterites because of its relatively low energy consumption and high nickel and cobalt recoveries.

TYPICAL USES OF STAINLESS STEEL IN A NICKEL PAL PLANT
STAGE STAINLESS STEEL USED
Ore preparation and slurrying Grade 310 or super duplex grades
Pressure leach circuit Grade 310 or super duplex grades
Counter current decantation
(ccd) circuit
Tanks - grade 316
Rakes and rabble arms - grade 316
Refinery (separating nickel, cobalt
products, making metal)
Process piping - grade 316
TOTAL APPROXIMATE STAINLESS
STEEL USAGE (PER MAJOR PLANT)
6 000 TONNES


BRIGHT FUTURE

Current trends undoubtedly point to an expanding role and bright future for hydrometallurgy in the mining and metallurgical industries. Along with this should come increased opportunity for the use of stainless steels.

Image: Nickel Heap Leaching trial at Radio Hill, WA.

This article was written by Alan Taylor, Chairman of consulting company International Project Development Services and convener of the ALTA Nickel/Cobalt 2001 (Perth, WA, May 15 - 18).

This article featured in Australian Stainless magazine - Issue 18,  May 2001.

2205 Golden Choice for Mine Upgrade

Two 2205 duplex stainless steel elution columns over 12 metres long have been installed in a replacement project at Kalgoorlie Consolidated Gold Mines in Western Australia. 

Elution columns are used in the mettalurgical process of extracting gold from carbon.

Carbon impregnated with gold is hot washed with caustic cyanide in the elution columns to dissolve the gold out of the carbon. The gold solution is pumped away while the barren carbon remains in the columns and then is removed for reuse.

The columns hold temperatures of 140°C and operate under pressures of 550 kilopascals (KPa).

he previous columns, constructed from grade 304 stainless steel, were beginning to fail due to pitting corrosion caused by chlorides carried over in the process water, combined with erosion corrosion on the internal surface. The tanks were in service for a total of five years.

Stainless steel supplier, ASSDA member Sandvik Australia, worked with a consultant to find a more suitable grade of stainless steel for the job.

2205 was chosen for its ability to provide a higher resistance to chloride attack. The grade also has improved hardness over grade 304, thereby offering better resistance to the erosion effect of the activated carbon.

Kalgoorlie Consolidated Gold Mines Mechanical Engineer Adrian Rowell, said the grade change was made to try to ensure the columns lasted the life of the mine.

"The plant is planned to operate for another 15 to 20 years," Mr Rowell said . "By shifting to 2205 we anticipate that the columns will last that long."

Fabricated by ASSDA member Specialised Engineering Services (WA) Pty Ltd, the columns were constructed from 2205 duplex stainless steel
8 millimetre plate, which offered a significant weight saving over the original 10 millimetre grade 304 vessel. The columns were fabricated to AS 1210 class 28 Pressure Vessels with a maximum design temperature of 150°C.

Each elution column is 12.4 metres long, 1.7 metres in diameter and positioned vertically.

This article featured in Australian Stainless magazine - Issue 18, May 2001.

Food Processing Plants Built on Stainless

A combination of grades 304 and 316L stainless steel has been utilised for all contact surfaces in Murray Goulburn's milk processing plant in Rochester, Victoria, which was upgraded in 2000.

The plant comprises an evaporator to concentrate cow's milk and spray dryer to produce various milk powders. Approximately 100 000 litres of milk is processed per hour, with the majority of product for export to over 100 countries. The evaporator and dryer represent more than half of the total project, a capital investment of around A$50 million.

The stainless surfaces and components carry milk feed, evaporated vapour, milk concentrate, milk powder, hot drying gas and cleaning chemicals of alkali and acid.

Ardmona tomato processing plant constructed entirely in stainless steel using grade 304.All product contact surfaces are of austenitic stainless steel grade AISI 304, with the 12m long evaporator tubes being produced from strip then rolled with the seam welded and bead rolled; the tubes have a 2B internal finish.

Principal contractor Niro Australia received instructions to proceed in July 1999 and conducted the first powder trials 14 months later, with commercial production starting November 2000.

To carry out the project, Niro involved Victorian fabricators Stainless Technology and PLC Engineering, though some fabrication was also conducted in New Zealand.

ASSDA member Alfa Laval supplied food grade stainless steel pumps, process valves, tank equipment, fittings and tubing worth over $2.5 million. The total supply was in excess of 40 tonnes and included 40km of tubing in sizes 1" to 6".

Grade 316L stainless steel was used for wetted parts (parts in contact with process fluids) and 304 for non-wetted areas. Products were generally supplied with a no.4 external surface finish; AS 1528 was used as the guideline for component standards.

Many of the process pumps and valves were chosen for their product handling characteristics. Specialist mixproof valves, which allow two different products to travel through the same valve without fear of intermixing, and high efficiency pumps were selected. Spillage-free mixproof valves were specified to prevent accidental discharge onto process floors and ensure a clean process environment, and rotary lobe pumps were selected for their gentle handling of cream products.

Pre-fabrication of many of the valve and pipework assemblies was carried out off-site in controlled environments. Due to the critical nature of the process applications, importance was placed on welding techniques and subsequent cleaning of welds. Valve manifolds were pre-fabricated and transported to site on completion, minimising the number of critical welds performed on site.

TOMATO PROCESSING
Fifty thousand tonnes of tomatoes have passed through Ardmona's processing plant in Mooroopna, Victoria, since it began operation a year ago.

The $15 million plant, which produces whole peeled and crushed tomatoes, was constructed entirely in stainless steel using grade 304 for the structural components and 316 tube and fittings for the wetted parts. Stainless steel was specified for its corrosion resistance and low maintenance, and to meet the health and safety requirements of a food processing plant.

Designed with a life expectancy of 30 years, the plant is capable of processing 40 tonnes of tomatoes per hour.

Ardmona's Engineering and Production Department, in conjunction with Italian firm Sasib Foods, were responsible for the design, engineering and construction aspects of the nine-month installation.

This article featured in Australian Stainless magazine - Issue 20, February 2002.

Australian Technology Advances Industry

A new technique for manufacturing high pressure cavity plate for heat exchange applications developed by the Australian stainless steel industry increases the options available to the food processing and manufacturing sectors. 

'Laser welded cavity plate' has been developed by ASSDA member J Furphy & Sons, a Shepparton fabricator of stainless steel tanks and processing equipment, as an alternative to resistance or plug welded dimple plate used for the heating or cooling jackets on stainless steel tanks, vessels and silos.

A wide range of industries stands to benefit from the new cavity plate, from dairy, brewing, food, wine, pulp and paper, chemical, pharmaceutical, refrigeration to textiles and manufacturing.

It is designed to be used in jacketed tanks, pressure vessels, shells and heads, troughing, chutes and hoppers, immersion plates, bank assemblies, baffles, ice-making plates, water chillers and food cookers.

The method of manufacture allows design flexibility enabling it to be tailored to specific performance requirements. It can be designed to suit both the flow characteristics of the refrigerant or heating medium and the required performance objective for the equipment by programming the cavity pattern and dimensions into a CNC controlled laser welding system.

The process involves laser welding two sheets of stainless steel in their flat form and inflating to form the cavity through which the cooling or heating medium is transferred.

The laser welds are exceptionally strong and have been burst tested in excess of 13 000 kPa, with most common demand being for operating pressures between 300 and 3 000kPa.

The product is available single embossed for uses where a flat inner wall is required or double embossed for immersion where both sides of the plate are utilised to heat or chill.

It is in use in chocolate crucibles in the confectionery industry as well as in Peerless Holdings’ edible oils processing tanks. Orbis Engineering has used the cavity plate in a cooling tunnel conveyor bed and Barry Brown & Sons has utlised it in on-farm milk silos. It has also been used in various major winery projects, including Peace Wines and Jindalee Estate, for fermentation and storage vessels.

Another ASSDA member, A&G Engineering of Griffith, has specialised in cavity plate for use as a cooling plate in wine vessels for a number of
years. This product also incorporates technology unique to Australia.

This article featured in Australian Stainless magazine - Issue 22, September 2002.

Stainless Braves the Elements

Advanced engineering solutions are required to handle conditions found on offshore drilling and processing platforms. The saltwater environment is highly corrosive, the flare presents extremes of temperature and the force of winds and currents is constant. The most durable and reliable materials need to be employed, which is why stainless steel plays and important part.

An impressive project making use of stainless' strength and corrosion-resistance is the Bayu Undan Gas Project in the Timor Sea, 5OOkm north of Darwin (pictured). Here, stainless steel is used to line the 18" pipelines between the processing platform and the wellhead platform 8km distant and in thousands of metres of pipes throughout the installation.

SPECIALIST BRIDGE BEARINGS
Stainless steel and high nickel alloy bearings support various bridges, including a 225m long bridge from the drilling platform to the flare. The bearings have been designed by specialist engineering and manufacturing firm Ludowici Ltd of Sydney, working closely with the project consultants TIGA JV of Perth. The bearing shown above is mirror polished to slide ±600mm while supporting a 900 tonne load, with operating temperatures up to 220°C due to the flare. In addition to continuous wave action, the bearing is designed to withstand 160 tonnes of transverse load due to gale force winds during tropical cyclones, as well as "bumps" during installation.

Bayu Undan is a project of Phillips Petroleum Company Australia Pty Ltd. Gas and liquid hydrocarbon reserves were discovered in 1995. It is estimated that the 25km by 15km field has a 25 year life and reserves of 350-400 million barrels of hydrocarbon liquids and 3.4 trillion cubic feet of gas. Work on the site is proceeding with full commercial production due by 2004. The first phase of the development, representing a US$1.4 billion investment, involves production and processing of wet gas. A second phase is planned to harvest the field's gas reserves.

Ludowici became involved in Bayu Undan in mid 2001, when it was chosen to design, manufacture, test and supply eight highly complex stainless steel pot-type bearings.

The design team drew on technical expertise of the Australian Stainless Steel Development Association and the Nickel Development Institute to produce a suitable design.

BUILT TO WITHSTAND WIND, WAVES AND WATER
The brief presented some unique challenges including massive steel superstructures requiring high-strength low-friction supports, to be left maintenance-free in a remote, aggressive tropical marine environment. Some were required to have uplift capacity, all were to be resistant to salt build-up, and all were required to be virtually maintenance free for a 25 year life. Whilst the majority of the bearing components ('pot' cylinders and pistons) were made from 316 and 316L stainless steel, the large-movement slide plates were made from grade 2205 duplex stainless steel, with a facing of polished Inconel 625, fully TIG welded around its perimeter. Thermal coefficients of expansion of mating parts were matched. Assembled bearings were tested in overload and friction, both at ambient temperature at 140°C.

The bearings were fabricated at the firm's Castle Hill, Sydney factory and transported to Batam, Indonesia where they were incorporated into the structure for the final trip to site.

The bearings measure up to 2m long and weigh up to 3 tonne each with attachments plates. They were also designed to withstand severe impact during installation.

The various bridges, platforms and piping are currently bring assembled.

For more information on Bayu Undan, visit www.offshore-technology.com/projects/bayu-undan

This article featured in Australian Stainless magazine - Issue 23, December 2002.

Stainless for power generation

At a time when so many industrial processes are computer-driven, there is still a place for human knowledge and experience in the highly specialised area of hydro-turbine manufacturing.

Steel Castings Pty Ltd, situated in Port Melbourne, has a reputation for precision moulding which has secured the firm contracts to produce two 'Pelton Runners' – the heart of the turbine – for a Victorian Hydro Power Station, working with the Norwegian designers, GE Australia and Acron Engineering.

Steel Castings have been making Peltons since the mid-90s. Measuring 2m in diameter and weighing in at 3.5 tonnes, these units are the largest so far. They are designed to withstand water cascading onto them from 400m above for 20 to 30 years to generate about five megawatts of electricity.

Despite their complex shape, the Peltons were cast in a single pour.

Technical Director Jim West explains the steps involved in achieving such a feat of engineering.

First a wooden pattern is made from drawings. Thousands of measurements must be checked. For example, there are 64 measurements for each of the Pelton Runner's 21 buckets. The pattern took about five weeks to make followed by a week of refinements.

One of the skills involved in pattern manufacture is estimating the contraction allowances for the shrinkage and distortions that occur during cooling and heat treatment. With only a 3mm tolerance window, this is something that can't be done by a computer, says Mr West. Once the pattern is complete, the mould and cores are produced from sand combined with a bonding agent – 17 tonnes of sand were required for this mould. The stainless steel used is CA6NM, a modified grade 410, poured at a temperature of nearly 1600ºC.

The mould is constructed so that the metal flows into all areas of the shape in less than 30 seconds of pouring time. The casting has to cool for seven days before it can be inspected. Then
the 'plumbing', the additional pieces which enable pouring the casting, is removed and the Pelton is heat treated at 1020ºC over a 23 hour cycle to strengthen the structure of the metal before final tempering and machining.

From drawing to installation the procedure takes about five months. The resulting finished technical marvel is worth hundreds of thousands of dollars.

ASSDA member Steel Castings Pty Ltd has its roots in the 19th century. It has operated in Port Melbourne since it was founded and employs a workforce of around 30 depending on current projects. The company's main business is manufacturing stainless steel and nickel-based alloy valves for the oil, gas and petrochemical industry. The firm also makes stainless steel ingots for the forging industry.

This article featured in Australian Stainless Issue 21 - June 2002.

Images:

Main image: mould nearing completion

Above right: cast detail of buckets